This invention relates to an apparatus and method for beading the projecting end of a tube to a header or tube sheet and which allows the beading operation to be carried out rapidly and effectively.
Large hot water heaters manufactured for commercial purposes basically comprise a cylindrical container having a top and bottom header with a multiplicity of open ended tubes extending through the container and which are held in place by the headers. Water within the container is heated by a gas flame applied to the bottom thereof and the tubes act to more effectively distribute the heat to the water and hence increase the heating efficiency.
In the conventional process of manufacturing the heaters, the tubes are inserted through apertures formed through the headers and the upper ends of the tubes are expanded into tight contact with the upper header. At the lower end, the projecting ends of the tubes are beaded or forced outward against the bottom side of the lower header. Beading insures a tight "heat sink" type of contact between the ends of the tubes and the lower header which is desirable to prevent the tube ends from burning which would otherwise cause the container to leak and hence reduce the effective lifetime of the heater.
In the past, beading has been carried out by the use of a small impact type of tool which is carried by a pneumatic hammer. In use, the operator must move the small impact tool to each angular position of the tube around its periphery in order to separately impact each position to form a 360.degree. bead. Beading with such a tool is extremely tedious, time consuming and very noisy.